Possible engine probs?

[k_b_stephens]

I was idling while talking with a friend in another boat and noticed my exhaust was a little colored. So glancing at the dash, the temp gauge was almost pegged at 240F. Quickly shut off the engine and opened the engine compartment. The coolant hose had collapsed, flattened, so very little water was going into the engine block. After waiting a few minutes, the hose reformed itself and i cranked the engine back up and it went back down to the normal 160F. The engine ran fine after that.
This week I'm replacing all of the coolant hoses, but my question is, what would cause the hose to collapse into itself? and what possible damage might have occurred even though its running fine now?

[DOCDRS]

curious, what boat do you have and year?

[k_b_stephens]

oops...that would help..

'99 Kanga

[Brian Raymond]

This is gonna sound good and bad. The top reasons for eng. overheat are worn impellars and clogged transmission coolers. Impellars should be replaced evey 100hrs. or at the beginning of every season(with a spare in the glove box), the tranny coolers checked regularly. If the above is done, it sounds like the mystery leaf or sandwich bag tha got on the water intake until you shut the motor off, floated away, and water could flow again. Replace the impellar immediately, when the motor gets that hot, inspection and replacement of the fiberglass mufflers may be necessary. When the motor gets that hot, it may cause the interior walls of the exhaust hose to collapse, causing future restrictions, inspect them, if they are blisstered on the exterior after the risers, replace everything aft, including ex. flanges. Deffinately replace the impellar first, if no signs of the above are seen, sweet. The next few times out, watch the temp. gauge closely, and be sensitive to driveability issues. If there was any intake, or head damage it might take 2or3 outings to verify. Let's bet on the impellar only. Keep me posted. Brian Raymond

Thanks for the info!

I'll have my local boat mechanic replace the impeller and inspect everything.

[k_b_stephens]

Thanks for the info!

Is the blueish colored smoke a "normal" indication that the engine is overheating? After it cooled down, the color went away.

[Brian Raymond]

By chance, did you notice if it smelled rich(gas) or more like oil? Usually when a motor first overheats, it will expell a white exhaust(steam), and have a distinctive noise through the exhaust system. A for sure indication is bubbled paint on the impellar housing, located at the front of the crankshaft. Brian Raymond

[k_b_stephens]

This weekend I took a look at the impellar and it was pretty rough. A lot of the flaps were missing. So this week I'm having the local mechanic replace it and take a look over the whole engine. Didn't see any bubbled paint anywhere....so perhaps thats a good sign.

*crosses fingers*

[Brian Raymond]

I hope all goes well with the check-up. Please keep me posted. Brian Raymond